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Advice please

valknightvalknight Posts: 3
in Problem solving
Advice on tiny black flies from window top seed trays, thanks

Posts

  • DovefromaboveDovefromabove Posts: 88,147
    Hi @valknight and welcome to the forum 😊 

    Theyre probably fungus flies also called sciatic flies ... they live in compost and are harmless but annoying. 



    Gardening in Central Norfolk on improved gritty moraine over chalk ... free-draining.





  • valknightvalknight Posts: 3
    Hi - Thanks for speedy reply.  As the seed trays were in the house it was annoying to see alot around so it's put me off growing seeds inside again even though magazines/websites suggest indoor window top planting without mentioning possible downsides as these flies. Thanks for helpful link and will have to rethink further seed planting inside.
  • DovefromaboveDovefromabove Posts: 88,147
    It sometimes happens if the compost  has been too wet for a while (sitting outside over winter maybe) ... if you can spread a bit out and dry it out slightly the larvae should die off ... or if you're only using a little you could zap it in the microwave or heat it to sterilizing point in the oven before using ... that'd kill them off  :D

    Gardening in Central Norfolk on improved gritty moraine over chalk ... free-draining.





  • clarke.bruntclarke.brunt Posts: 215
    They're not harmless with 'very slow' seedlings - like the cactus I grow! The larvae of the sciarid flies like to hollow-out the inside of the blob-like seedlings. With anything faster growing, agreed that they're not likely to make much impression on the seedlings.

    Agreed that they usually come with the compost, but obviously if you've got the flies around anyway, they might move in to seedling pots - and they can soon multiply. So far this year, I spotted a couple of the larvae  (tiny, translucent whitish, black spot at one end) writhing around in my pots of cactus seedlings (but no adult flies) - I removed the larvae and haven't seen any since. Not practical with greater numbers - they're usually hidden below the surface.
  • valknightvalknight Posts: 3
    Thanks for all your help.  Hmm, who said gardening was easy.  Monty Don makes everything look so relaxed so back to the drawing board then.
  • CeresCeres Posts: 2,698
    valknight said:
    Thanks for all your help.  Hmm, who said gardening was easy.  Monty Don makes everything look so relaxed so back to the drawing board then.
    We never see the outtakes. It's easy to look relaxed if you have helpers and an editing suite.
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